fix(posthog): make OMO_DISABLE_POSTHOG env parsing case-insensitive and trim-tolerant (refs #4368)

[MoerAI]

Summary

Hardens telemetry env-var parsing so case-variant and whitespace-padded values are honored. The behavior change is strictly additive: every value already disabled today (true, 1, 0, false, no) is still disabled; only previously-ignored variants (TRUE, Yes, 1, true, etc.) are now respected.

Scope clarification (re: #4368)

Issue #4368 reports OMO_DISABLE_POSTHOG=1 not disabling telemetry. The pre-fix code already strictly matched === "1", so this PR is NOT a guaranteed fix for that specific reproduction — the user's reported value already worked under the old code. A full codebase audit (every new PostHog(...), every capture(), every trackActive(), every CLI entrypoint) confirmed there is no telemetry capture path that bypasses shouldDisablePostHog(), so the residual cause in #4368 is most likely environment-side (env var not propagated to the spawned bun process, or a broken plugin install — the oh-my-openagent unknown in their doctor output is consistent with a missing ~/.cache/opencode/node_modules/oh-my-openagent).

Keeping Refs #4368 rather than Fixes #4368 so the issue stays open until the reporter's actual root cause is identified. The robustness improvement here closes the door on a related class of failures (case/whitespace mismatch on shell/CI env vars) that other users will eventually hit.

Root Cause

shouldDisablePostHog() in src/shared/posthog.ts previously compared OMO_DISABLE_POSTHOG against the strict string literals "true" and "1". Shell environments and config tooling frequently emit case-variant or padded values such as TRUE, True, Yes, 1, or true; those values silently fell through to the default "capture telemetry" branch, even though the user clearly intended to opt out.

The companion var OMO_SEND_ANONYMOUS_TELEMETRY was already normalized via .trim().toLowerCase() before isFalsy() — the disable path just never received the same treatment.

Changes

File	Change
src/shared/posthog.ts	Add symmetric isTruthy() helper; normalize OMO_DISABLE_POSTHOG with .trim().toLowerCase() before matching (mirror of the existing OMO_SEND_ANONYMOUS_TELEMETRY path)
src/shared/posthog.test.ts	12 new given/when/then cases covering case-variant + whitespace inputs for both env vars

Diff: +67 / −1 across 2 files. fix() only — no behavior change for values already handled (true, 1, 0, false, no).

Reproduction (before fix)

(fail) posthog disable env var parsing > treats OMO_DISABLE_POSTHOG="TRUE" as disabled
(fail) posthog disable env var parsing > treats OMO_DISABLE_POSTHOG="True" as disabled
(fail) posthog disable env var parsing > treats OMO_DISABLE_POSTHOG="Yes" as disabled
(fail) posthog disable env var parsing > treats OMO_DISABLE_POSTHOG="YES" as disabled
(fail) posthog disable env var parsing > treats OMO_DISABLE_POSTHOG=" 1 " as disabled
(fail) posthog disable env var parsing > treats OMO_DISABLE_POSTHOG=" true " as disabled

 10 pass
 6 fail
 32 expect() calls

Verification (after fix)

bun test src/shared/posthog.test.ts
 16 pass
 0 fail
 32 expect() calls
Ran 16 tests across 1 file. [438.00ms]

Test

• Regression test: src/shared/posthog.test.ts (12 new cases under describe("posthog disable env var parsing"))
• Related telemetry suite: bun test src/shared/posthog{,-activity-state}.test.ts src/cli/cli-installer.telemetry.test.ts src/cli/run/runner.telemetry.test.ts src/index.telemetry.test.ts — 25 pass
• Typecheck: bun run typecheck — clean

Refs #4368

[MoerAI]

I have read the CLA Document and I hereby sign the CLA

[code-yeongyu]

[sisyphus-dev] Reviewed and QA verified. The exact #4368 env values are already honored on current dev, so this is not a guaranteed root-cause fix for that report, but the PR is a clean narrow hardening change: it normalizes case/whitespace for opt-out values without adding config surface or changing telemetry payloads. Local QA on a merge with current dev: telemetry regression suite passed, typecheck passed, build passed.