fix(agera): sync with alien-signals v3.2.1

[dangreen]

Ports upstream alien-signals changes since the last sync point (836130c, v3.1.2) up to c00e639 (v3.2.1 + 2 commits). Each upstream change was analyzed, reproduced where applicable, and either ported or deliberately skipped. Full report: packages/agera/history/v3.2.1-c00e639.md.

Ported

Upstream	What it fixes
fb17aed	refactor: hoist trigger sub flag reset out of propagate loop
ad52894 + b83cf94 + fbabdbd	crash + disposed-effect resurrection when user code disposes effects/scopes during checkDirty update (alien-signals#109, alien-signals#115) — reproduced in agera before the port
c28a596	effect not responding to computed changes read through effectScope (alien-signals#105) — reproduced
cf75b33 + 4b15362	stack overflow when destroy calls own stop() + effect resurrection when destroy disposes it (alien-signals#113) — reproduced
9daa5c3 + c00e639	flush crash when writing a signal inside trigger after reading it (alien-signals#122) — reproduced

Skipped deliberately

• 7e53655 + d4d0449 (runDepth/innerWrite, alien-signals#112) — the alien-signals#99 bug class is already covered by agera's flushDepth mechanism, which additionally fixes lost notifications that upstream still has at HEAD. Porting was prototyped: zero observable effect. Regression tests added instead.
• 713a1c6 (LIFO disposal, alien-signals#116) — redefines cleanup ordering; agera keeps its own contract (own destroy first, children FIFO). Accepted divergences documented in the history report.

History

• New sync snapshot packages/agera/history/v3.2.1-c00e639.diff (flattened upstream vs src/internals) and sync report v3.2.1-c00e639.md.

Tests

• agera: 97 passed + 2 expected fail (was 77), 20 new regression tests, oxlint/tsc clean.
• size-limit: green across the whole monorepo, per-package builds verified for agera/kida/store (sizes actually shrank thanks to the walk-up removal in the effectScope port).
• kida: 61 passed.

[codecov]

Codecov Report

❌ Patch coverage is 96.77419% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 83.79%. Comparing base (1410c97) to head (02b42ea).

Files with missing lines	Patch %	Lines
packages/agera/src/internals/system.ts	96.77%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #160      +/-   ##
==========================================
- Coverage   83.81%   83.79%   -0.03%     
==========================================
  Files         137      137              
  Lines        2966     2962       -4     
  Branches      555      558       +3     
==========================================
- Hits         2486     2482       -4     
  Misses        340      340              
  Partials      140      140              

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[Copilot]

Pull request overview

This PR updates agera’s internal reactive runtime to match upstream alien-signals v3.2.1 behavior (plus two additional commits), primarily addressing several edge-case crashes/resurrection scenarios involving trigger, checkDirty, effectScope, and effect destroy/stop semantics.

Changes:

• Ports upstream runtime fixes into packages/agera/src/internals/system.ts (trigger flush crash prevention, resilient dirty-checking under graph mutation, effect destroy recursion/resurrection handling, and effectScope participation in propagation).
• Adds a substantial set of regression tests covering the newly-ported behaviors and prior crash cases.
• Updates size-limit thresholds for agera, kida, and store based on the new bundle output, plus adds a new sync snapshot + report under packages/agera/history/.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/agera/src/internals/system.ts	Ports alien-signals v3.2.1 runtime semantics and multiple bug fixes into agera’s core reactive system.
packages/agera/src/effect.spec.ts	Adds regression tests for effect cleanup/disposal edge cases, checkDirty mutation resilience, and effectScope propagation behavior.
packages/agera/src/signal.spec.ts	Adds regression tests for writing a signal inside trigger after reading it.
packages/agera/history/v3.2.1-c00e639.md	Adds a sync report documenting what was ported vs deliberately skipped and why.
packages/agera/history/v3.2.1-c00e639.diff	Adds a flattened upstream-vs-agera snapshot diff for auditability of the sync point.
packages/agera/.size-limit.json	Updates agera bundle size limits to reflect reduced output size after the port.
packages/kida/.size-limit.json	Updates kida bundle size limits to reflect reduced output size after the port.
packages/store/.size-limit.json	Updates store bundle size limits to reflect reduced output size after the port.

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