Fix issues 288 289 290 291

[emdevelopa]

Pull Request Description

This PR addresses the following features and security improvements:

• Off-Chain Notification Webhooks: Added an event listener microservice in services/notifier to subscribe to Soroban events and send webhooks. (closes Off-Chain Notification Event Webhooks via Indexer #288)
• Decentralized Session Notes & IPFS Encryption: Updated the Session struct to use encrypted_notes_cid allowing experts to store encrypted session notes via IPFS. (closes Decentralized Session Notes & IPFS Encryption #289)
• Reentrancy Guard: Added a new security module with a ReentrancyGuard modifier to prevent nested recursive invocations in settle_session and withdraw_accrued. (closes Reentrancy Guard Modifier for External Contract Calls #290)
• Emergency Pause / Circuit Breaker: Added emergency_pause() and emergency_unpause() to the contract controlled by SuperAdmin. Enhanced functions like start_session, initialize_fixed_price_session, and reserve_session to check for is_emergency_paused. Withdrawals and settlements remain active during the pause to allow users to retrieve funds safely. (closes Emergency Pause ("Circuit Breaker") for Entire Contract #291)

Summary by CodeRabbit

• New Features

  • Added an emergency pause mode to temporarily stop key session actions and expose pause status.
  • Added a notifier service that forwards contract events to a configured webhook.

• Bug Fixes

  • Improved session cancellation and fund handling protections.
  • Strengthened reentrancy safeguards to help prevent duplicate or unsafe contract calls.
  • Updated session note storage and related migration handling to keep data consistent.

[coderabbitai]

Caution

Review failed

Pull request was closed or merged during review

📝 Walkthrough

Note: range_3783_placeholder above is a placeholder that does not exist in <all_range_ids>; range_4c270bcc651a (removal of manual lock helpers) was assigned to the reentrancy layer. All 40 provided rangeIds are assigned exactly once across layers.

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Walkthrough

Introduces a centralized ReentrancyGuard in a new security module replacing manual lock helpers across all guarded contract functions, adds emergency_pause/emergency_unpause admin entrypoints with checks in session-creating functions, renames the Session field from encrypted_notes_hash to encrypted_notes_cid, extends the Error enum with new variants, and adds a TypeScript notifier microservice that polls Soroban events and POSTs them to a webhook.

Changes

Contract: ReentrancyGuard, Emergency Pause, CID field rename

Layer / File(s)	Summary
Error enum variants and ReentrancyGuard implementation contracts/src/errors.rs, contracts/src/security.rs, contracts/src/lib.rs	Renames InsuffTreasuryBal → InsufficientTreasuryBalance and Reentrancy → ReentrantCall; adds InsufficientAntiSpamDeposit, CircuitBreakerActive, and SessionNotExpired error variants. Adds ReentrancyGuard struct with non_reentrant and clear using a temporary storage boolean. Removes the local Error enum from lib.rs in favor of pub use errors::Error and declares pub mod security.
Reentrancy refactor across session functions contracts/src/disputes.rs, contracts/src/lib.rs	Replaces set_reentrancy_lock/assert_not_locked with ReentrancyGuard::non_reentrant and ReentrancyGuard::clear on all early-return and success paths in settle_session, end_session, internal_settle, close_session, claim_no_show_refund, withdraw_accrued, and cancel_session_by_expert. Removes manual lock helper functions.
Emergency pause entrypoints and session guards contracts/src/lib.rs	Adds is_emergency_paused, emergency_pause, and emergency_unpause methods gated to SuperAdmin; wires an emergency pause check into initialize_fixed_price_session, start_session, and reserve_session to return ProtocolPaused early.
Session encrypted_notes_cid field rename and propagation contracts/src/lib.rs, contracts/src/migrations.rs, contracts/src/identity.rs, .gitignore	Renames Session.encrypted_notes_hash to encrypted_notes_cid across the struct definition, all session constructors, update_session_notes, request_data_deletion, the v1→v2 migration re-hydration and comments, the identity deletion comment, and the unit test assertion.

Notifier Microservice

Layer / File(s)	Summary
Notifier service implementation and package setup services/notifier/package.json, services/notifier/index.ts	Adds notifier-service package with ts-node entry point and @stellar/stellar-sdk/axios/dotenv dependencies. Implements sendWebhook with exponential-backoff retries (up to 5) and listenEvents polling Soroban contract events every 5 seconds, advancing an internal ledger cursor and delivering events to a configured webhook URL.

Sequence Diagram(s)

sequenceDiagram
  participant listenEvents
  participant SorobanRPC
  participant sendWebhook
  participant Webhook

  listenEvents->>SorobanRPC: getLatestLedger()
  SorobanRPC-->>listenEvents: latestLedger (cursor init)

  loop every 5 seconds
    listenEvents->>SorobanRPC: getContractEvents(cursor)
    SorobanRPC-->>listenEvents: events[]
    loop for each event
      listenEvents->>sendWebhook: sendWebhook(event)
      sendWebhook->>Webhook: POST {event_type, contract_id, topic, value, timestamp}
      alt success
        Webhook-->>sendWebhook: 2xx
      else failure with retries
        Webhook-->>sendWebhook: error
        sendWebhook->>sendWebhook: retry with exponential backoff (max 5)
      end
    end
    listenEvents->>listenEvents: advance cursor to latestLedger
  end

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Estimated code review effort

🎯 4 (Complex) | ⏱️ ~60 minutes

Possibly related issues

• Reentrancy Guard Modifier for External Contract Calls #290 — PR directly implements the ReentrancyGuard/Error::ReentrantCall mechanism and migrates all guarded calls to it.
• Emergency Pause ("Circuit Breaker") for Entire Contract #291 — PR adds the circuit-breaker emergency_pause/emergency_unpause entrypoints and wires pause checks into session-creating functions, matching the issue's objective.
• Off-Chain Notification Event Webhooks via Indexer #288 — PR introduces the services/notifier/ Soroban event-to-webhook microservice described in the issue.

Possibly related PRs

• LightForgeHub/SkillSphere-Dapp#157: Both PRs modify reentrancy protection and pause/session lifecycle logic in the contract's settlement and close paths.
• LightForgeHub/SkillSphere-Dapp#244: Both PRs touch cancel_session_by_expert in disputes.rs around reentrancy guard setup and clearing.
• LightForgeHub/SkillSphere-Dapp#279: Both PRs modify the request_data_deletion tombstone path for session encrypted notes, which this PR renames to encrypted_notes_cid.

Poem

🐇 Hop hop, the guard is set,
No reentrant calls slip through the net.
Emergency pause? The circuit breaks!
CID replaces hash — what a wake!
A notifier polls with webhooks bright,
The rabbit keeps the ledger right. ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title only lists issue numbers and does not describe the actual changes in the PR.	Use a concise, descriptive title that summarizes the main change, such as adding webhooks, IPFS notes, reentrancy protection, and emergency pause support.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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