[codex] Add Linear issue type decision guide

[cjarguello]

Summary

• Add the canonical Linear issue type decision guide at linear/docs/process/linear_issue_type_decision_guide_v1.md.
• Add minimal pointers from the active Linear operating model, operating guide, evidence contract, and changelog.
• Make issue type assignment evidence-based, keep Design narrow, and make Release rare.

Validation

• git status --short
• git diff --cached --check
• grep -R "linear_issue_type_decision_guide_v1" -n linear/docs/process
• checked touched files for stale /Users/cjarguello or /cjar... paths

Notes

• Did not mutate live Linear issues.
• Pre-existing unrelated local edits were left unstaged: audit_ctl.sh, config/repo_registry.tsv, and tests/test_audit_tools.sh.

[cjarguello]

Follow-up update after CJ clarification:

• Tightened Feature vs Chore: upgraded existing capability with new real functionality is Feature.
• Tightened Bug vs Chore: if expected behavior did not work and evidence exists, classify as Bug even if the implementation fix is refactor/hardening.
• Tightened Plan: parent mini-project/epic with real subtickets; not checklist or vague-spec bucket.
• Tightened Design: serious design artifact/approval only; split design and implementation when both are needed.
• Added tie-breaker matrix and a short routing note separating issue type from QA/PM routing.
• Recorded routing-rule seed on BIT-178 without changing assignee/delegate/status.

[cjarguello]

Follow-up update: converted the issue-type guide from prose-first to machine-readable-first.

Added:

• linear/contracts/linear_type_classifier_v1.json as the automation source for issue type + default routing decisions.
• linear/docs/process/linear_type_classifier_corrections_v1.md as the single human correction / learning log.
• Linear Classification intake block requirement in the guide/evidence contract.
• LinearBotEngine classifier parsing/enforcement so Ready/In Progress gate fails closed when the intake block is missing or the label disagrees with the deterministic classifier.
• Tests covering missing intake, type mismatch, and PM-skip routing for technical chores.

Validation:

• python3 -m json.tool linear/contracts/linear_type_classifier_v1.json >/dev/null
• python3 -m unittest linear.tests.test_engine
• git diff --check

[cjarguello]

Hardening update from Pauli review findings:

• Engine now loads/interprets linear/contracts/linear_type_classifier_v1.json for required intake fields, output values/aliases, boolean fields, type decision order, and routing defaults instead of duplicating the classifier logic entirely in Python.
• Invalid intake now fails closed: unknown Output values and non-yes/no booleans trigger needs-type + Backlog instead of falling through to Chore.
• Strict classifier enforcement is limited to Ready gate so existing In Progress issues are not back-migrated without a migration pass.
• Routing defaults are documented as advisory until wired to label/status automation.
• Added tests for invalid intake, In Progress grandfathering, and contract parity.

Validation:

• python3 -m json.tool linear/contracts/linear_type_classifier_v1.json >/dev/null
• python3 -m unittest linear.tests.test_engine
• git diff --check

[cjarguello]

Linear follow-up / Icebox defaulting update:

Observed while creating follow-up issues that state: "Backlog" by name returned new Product Development issues in Icebox 🧊. Correcting by concrete Backlog status ID worked.

Actions taken:

• Created BIT-442 — Fix Linear issue creation defaulting to Icebox instead of Backlog, classified as Bug.
• Corrected BIT-440/BIT-441/BIT-442 to Backlog using status ID 162716a8-ffa4-43ea-9e0d-c48fdb8054bc.
• Added a temporary workaround note to linear_operating_guide_v3.md and changelog so Codex does not rely on memory while BIT-442 is open.

Validation re-run:

• python3 -m json.tool linear/contracts/linear_type_classifier_v1.json >/dev/null
• python3 -m unittest linear.tests.test_engine
• git diff --check

[cjarguello]

Fixup: PR #97 now includes the classifier-corrections fixture + test so the required validation command passes:

• linear/tests/fixtures/linear_type_classifier_corrections_v1.json
• linear/tests/test_classifier_corrections.py
• helper script linear/scripts/record_type_classifier_correction.py

Commit: b8106e7 (cherry-picked from the BIT-441 work so python3 -m unittest linear.tests.test_engine linear.tests.test_classifier_corrections succeeds).

[cjarguello]

Cleanup update: investigated the lingering local audit/hygiene edits. They were an older uncommitted copy/subset of upstream origin/main commit e0d8053 (Fix T3 cleanup top-level truth). Rebased this PR onto origin/main and force-pushed.

Current head: 67881f8.
Validation now passes:

• python3 -m json.tool linear/contracts/linear_type_classifier_v1.json >/dev/null
• python3 -m unittest linear.tests.test_engine
• python3 -m unittest linear.tests.test_engine linear.tests.test_classifier_corrections
• git diff --check

Working tree is clean; no lingering uncommitted audit/hygiene edits remain.