fix(agent-manager): share async process snapshots

[codeaholicguy]

Summary

• capture and enrich relevant process data once per AgentManager refresh using asynchronous child-process execution
• slice the union snapshot by each adapter's declared processNames before dispatch, preserving the historical candidate pools for Pi and Gemini broad token matchers
• defensively scope hand-built adapter contexts and normalize Windows separators/.exe suffixes through one shared executable filter
• keep Ink incremental rendering enabled and retain the existing 3000 ms polling cadence
• preserve adapter matching, registry behavior, sorting, enrichment, platform fallbacks, and partial failure handling
• replace the unsupported async execFile stdio option with an explicit 10 MiB maxBuffer

Validation

• TDD red: six deterministic failures proved the full-union leak, missing shared filter, missing async buffer, and Windows-path rejection
• focused manager/process/Pi/Gemini: 4 files, 131 tests passing
• all seven adapter suites: 7 files, 296 tests passing
• regression gate: foreign-argument test fails when manager slicing is removed and passes after restoration
• agent-manager full: 24 files, 510 tests passing; lint, typecheck, and build passing
• CLI agent/console focused: 23 files, 207 tests passing
• CLI full: 81 files, 967 tests passing; lint and build passing
• repository full serial tests across all 6 projects passing
• repository lint passing with 0 errors (6 existing warnings); repository build passing

Compatibility and risk

• snapshot capture still performs exactly one base ps -axo scan per refresh; per-adapter slicing is in-memory only
• snapshot and enrichment failures remain best-effort, and adapter failures still yield partial manager results
• legacy third-party adapters without processNames continue through the unchanged no-context path
• standalone built-in adapter calls retain asynchronous local capture