feat(runtime): extract action-execution subsystem — ADR-0076 D11 step ③ PR-8 (#2462)

16 helpers (~560 lines) behind server-registered business actions move
to action-execution.ts on the narrow ActionExecutionDeps slice
(resolveService + getObjectQL — deliberately NO env-resolution state;
that stays with route handlers). The ADR-0104 warn-once statics
(actionParamsStrict/warnActionParamsOnce) ride along as module
functions — they were HttpDispatcher statics the extracted body
referenced, which would have made a value-cycle back into the
dispatcher.

Dispatcher keeps 4 thin delegates that have in-class callers
(callData/enforceActionParams/actionPermissionError/buildActionSession);
the 12 internal-only helpers are invoked directly on the module (5 call
sites in buildMcpBridge/handleActions rewired).

This is the pre-cut for PR-9: /actions and /mcp become mechanical
domain extractions now that their shared machinery is a module.

Verified: runtime 649, http-conformance 41, dogfood 351 (full-build
first — the suite needs every example/connector dist), dependent
closure DTS green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: os-zhuang

.changeset/runtime-action-execution-module.md

@@ -0,0 +1,17 @@
+---
+"@objectstack/runtime": minor
+---
+
+feat(runtime): extract the action-execution subsystem from the dispatcher — ADR-0076 D11 step ③, PR-8 (#2462)
+
+The 16-helper machinery behind server-registered business actions
+(declaration collection/resolution, ADR-0104 param enforcement, the
+permission/AI-exposure gates, the engine facade + session shape, invocation,
+and the `callData` protocol/ObjectQL bridge — ~560 lines) moves to
+`action-execution.ts`, depending only on the narrow `ActionExecutionDeps`
+slice (resolveService + getObjectQL; NO env-resolution state). The
+ADR-0104 warn-once statics ride along as module functions. The dispatcher
+keeps four thin delegates with in-class callers; twelve internal-only
+helpers are called directly on the module. This is the pre-cut that turns
+the `/actions` and `/mcp` domain extractions into mechanical moves (PR-9).
+Zero behavior change — runtime 649, http-conformance 41, dogfood 351 green.