[modules→tinybus] bug: a failed TinyComputer reinitialize leaves the old config fingerprint recorded #14

Parent: tinyhumansai#8056

Context

modules/desktop.rs:53-72 compares the config fingerprint with last_config(), then calls reinitialize_module. On error it returns through ? and leaves previous at the old fingerprint, even though the module may have half-applied the new config. If the user then reverts to the old config, the fingerprints match, the reinitialize is skipped, and the module keeps serving the half-applied config. search/proxy.rs:100 does this correctly: it clears held before reinitializing.

Scope

• Set the recorded fingerprint to None before calling reinitialize_module, and record the new one only after it succeeds.
• Regression test in desktop_tests.rs, with a failing reinitialize stub.

Acceptance criteria

• A failed reinitialize followed by a call with the previous config reinitializes again.
• Regression test: fail on config B, then call with config A, and the reinitialize is attempted.

Verification

pnpm debug rust modules::desktop

Agent brief

Depends on: none · Blocks: #33 (ReconfigurableModule adoption carries the same rule)

Files to consider: modules/desktop.rs:36-76, modules/search/proxy.rs:90-120 (the correct shape), modules/desktop_tests.rs

Workflow: implementing-an-epic step · Subagents: systematic-debugger, code-reviewer