infra: move developer-tools to top-level section (#251)

## Summary

- Moves `docs/references/developer-tools.md` →
`docs/developer-tools/index.md`
- Updates sidebar slug from `references/developer-tools` to
`developer-tools` (URL: `/developer-tools`)
- Patches internal links in `references/index.md`,
`guides/ai-coding-agents.md`,
`guides/canister-calls/calling-from-clients.md`, and
`guides/security/identity-and-access-management.mdx` (the last two links
added by PR #253 after this branch was originally created)

The page is a navigational toolchain catalogue, not a spec or lookup
reference. Its sidebar placement was already top-level (outside the
References accordion), but the URL said `/references/developer-tools`.
This aligns the URL with the navigational role and opens the section for
future sub-pages.

## Sync recommendation

`hand-written`

Author: marc0olo

docs/references/developer-tools.md docs/developer-tools/index.mddocs/references/developer-tools.md renamed to docs/developer-tools/index.md

@@ -96,7 +96,7 @@ ICP skills are available without authentication:
 ## Next steps
 
 - [skills.internetcomputer.org](https://skills.internetcomputer.org): browse all available ICP skills
-- [Developer tools](../references/developer-tools.md): icp-cli, CDKs, and other tools in the ICP toolchain
+- [Developer tools](../developer-tools/index.md): icp-cli, CDKs, and other tools in the ICP toolchain
 - [Quickstart](../getting-started/quickstart.md): deploy your first canister with icp-cli
 
 <!-- Upstream: informed by dfinity/icskills — README.md, skills/*/SKILL.md -->

docs/guides/ai-coding-agents.md

@@ -61,7 +61,7 @@ Crate documentation: [docs.rs/ic-agent](https://docs.rs/ic-agent/latest/ic_agent
 
 ### Community agents
 
-Community-maintained agents are available for Go, Java/Android, Dart/Flutter, .NET, Elixir, and C. See [Developer Tools](../../references/developer-tools.md#other-languages) for the full list.
+Community-maintained agents are available for Go, Java/Android, Dart/Flutter, .NET, Elixir, and C. See [Developer Tools](../../developer-tools/index.md#other-languages) for the full list.
 
 ## JavaScript / TypeScript: using the agent
 

docs/guides/canister-calls/calling-from-clients.md

@@ -79,7 +79,7 @@ Implementing user authentication and canister calls yourself in your web app is
 
 ### Recommendation
 
--   Consider using an identity provider such as [Internet Identity](https://github.com/dfinity/internet-identity) for authentication, and use the [ICP JavaScript agent](../../references/developer-tools.md#javascript--typescript) for making canister calls.
+-   Consider using an identity provider such as [Internet Identity](https://github.com/dfinity/internet-identity) for authentication, and use the [ICP JavaScript agent](../../developer-tools/index.md#javascript--typescript) for making canister calls.
 
 -   You may consider alternative authentication frameworks on ICP for authentication.
 
@@ -99,7 +99,7 @@ The auth-client supports [idle timeouts](https://js.icp.build/auth/latest/api/cl
 
 ### Security concern
 
-`agent.fetchRootKey()` can be used in the [ICP JavaScript agent](../../references/developer-tools.md#javascript--typescript) to fetch the root subnet threshold public key from a status call in test environments. This key is used to verify threshold signatures on certified data received through canister update calls. Using this method in a production web app gives an attacker the option to supply their own public key, invalidating all authenticity guarantees of update responses.
+`agent.fetchRootKey()` can be used in the [ICP JavaScript agent](../../developer-tools/index.md#javascript--typescript) to fetch the root subnet threshold public key from a status call in test environments. This key is used to verify threshold signatures on certified data received through canister update calls. Using this method in a production web app gives an attacker the option to supply their own public key, invalidating all authenticity guarantees of update responses.
 
 ### Recommendation
 

docs/guides/security/identity-and-access-management.mdx

@@ -7,10 +7,6 @@ sidebar:
 
 Technical reference material for ICP development. These pages cover exact specifications, canister IDs, costs, and error codes.
 
-## Tools
-
-- **[Developer Tools](developer-tools.md)**: icp-cli, CDKs, JS SDK, PocketIC, ICP Ninja, and other toolchain components.
-
 ## Canisters
 
 - **[Management Canister](management-canister.md)**: API reference for the IC management canister (`aaaaa-aa`): canister lifecycle, signing, randomness, and more.

docs/references/index.md

@@ -190,7 +190,7 @@ export const sidebar = [
       },
     ],
   },
-  { slug: "references/developer-tools", label: "Developer tools" },
+  { slug: "developer-tools", label: "Developer tools" },
   {
     label: "References",
     collapsed: true,