chore(main): release 2.4.0

[github-actions]

🤖 I have created a release beep boop

2.4.0 (2026-08-14)

Features

• index: derive a per-repo namespace on first index; add namespaces command (#239) (8fd50ed), closes #232
• make explain concise and non-streaming (#222) (2a5fe79)

Bug Fixes

• clustering: match kind_weight on ReferenceKind, not its string form (#233) (a90dfe7), closes #226
• impact: distinguish an unresolved symbol from one with no callers (#235) (d2f83bd), closes #228
• index: stop deleting unreadable files from the index (#234) (f591ab4), closes #227
• scip: treat ForwardDefinition as a definition, not a reference (#236) (c8dbf9d), closes #230
• search: stop RRF_MIN_SCORE deleting rank-0 results; apply test penalty once (#238) (dc8c0c3), closes #231
• serve: stop concurrent requests from re-naming the same communities (#225) (4f2b5ae)
• traversal: walk only impact edges, not all twelve reference kinds (#237) (f9cc818), closes #229

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[github-actions]

🤖 Created releases:

• v2.4.0

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