fix(util): no filesystem side effects at global module load

[kitlangton]

What

Importing @opencode-ai/util/global wrote to disk through three top-level awaits. This violates Effect layer acquisition discipline and prevents Cloudflare workerd startup.

How

• Keep module scope and every static Global.Path property pure, with no top-level await or filesystem I/O.
• Create data, config, state, log, bin, repos, and tmp directories during Global layer acquisition.
• Canonicalize the default tmp path after acquisition; explicit layerWith tmp overrides retain precedence.
• Make the file logger create its target parent before opening the file, since observability can initialize before Global acquisition.
• Keep existing static Global.Path consumers unchanged; no non-test consumer reads Global.Path.tmp.

Testing

• packages/util: bunx tsgo --noEmit
• packages/util: bun test (fresh-process property-access purity, acquisition, canonicalization, and override precedence)
• packages/core: bunx tsgo --noEmit
• packages/core: bun test test/instruction-discovery.test.ts test/effect/observability.test.ts
• packages/cli: bun test test/service.test.ts -t "managed service writes its registration once"
• packages/server: bun test test/process.test.ts
• Pre-push workspace typecheck: 33/33 tasks passed

[kitlangton]

Confirmed and fixed the remaining regressions. Local logging was acquired before the Global layer, so Logger.toFile attempted to open Global.Path.log before its parent existed; managed-service subprocesses exited at the same point before publishing registration. fileLogger now creates the target parent directory immediately before opening the file, without restoring import-time I/O.

Also replaced InstructionDiscovery's unwritable /global fixture path now that layerWith acquires its configured directories. Focused results: util 6/6, InstructionDiscovery + observability 13/13, and the previously timing-out managed service writes its registration once passes. Full service run passed all CI-reported lifecycle cases; the separate a failed service stays registered... timeout reproduces unchanged on origin/v2 when run alone.