fix(pprof): bind to configurable loopback address instead of :6060

[s0up4200]

pprof hardcoded :6060 (i.e. 0.0.0.0:6060), which fails to bind when another listener in the same network namespace already owns the port — e.g. running qui behind a Tailscale sidecar that serves :6060. The profiler then silently never starts (listen tcp :6060: bind: address already in use), so QUI__PPROF_ENABLED=true looks enabled but yields nothing to profile.

This defaults the pprof bind address to 127.0.0.1:6060 (also safer than a wildcard) and adds QUI__PPROF_ADDR / pprofAddr to override it. With loopback binding, an existing tailscale serve :6060 -> http://127.0.0.1:6060 mapping works as intended.

Summary by CodeRabbit

• New Features

  • The pprof profiling listener address is now configurable via the QUI__PPROF_ADDR environment variable or configuration file, with a default of 127.0.0.1:6060.

• Documentation

  • Updated configuration documentation to reflect the new pprof address configuration option.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: e300033f-2df8-4b83-ace0-58e7380e4ea7

📥 Commits

Reviewing files that changed from the base of the PR and between a69ae69 and 7df97f2.

📒 Files selected for processing (5)

• cmd/qui/main.go
• documentation/docs/configuration/environment.md
• documentation/docs/configuration/reference.md
• internal/config/config.go
• internal/domain/config.go

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Walkthrough

A new PprofAddr configuration field is added to the Config struct and wired through Viper with a default of 127.0.0.1:6060, an env binding to QUI__PPROF_ADDR, and hydration into the loaded config. The pprof HTTP server startup now uses this configurable address instead of the hardcoded :6060. CLI flag help text and configuration docs are updated accordingly.

Changes

Configurable pprof bind address

Layer / File(s)	Summary
Config struct and Viper wiring internal/domain/config.go, internal/config/config.go	PprofAddr string field added to Config with toml/mapstructure tags; Viper default (127.0.0.1:6060), env binding (QUI__PPROF_ADDR), and hydration into c.Config.PprofAddr are registered.
Server startup, flag text, and docs cmd/qui/main.go, documentation/docs/configuration/environment.md, documentation/docs/configuration/reference.md	Server startup resolves pprofAddr from cfg.Config.PprofAddr (falls back to 127.0.0.1:6060) and passes it to http.ListenAndServe; --pprof flag help text updated; QUI__PPROF_ADDR and pprofAddr entries added to environment and reference docs.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐇 A bunny once tripped on a fixed :6060,
Now addresses flex, no more rigid voodoo.
QUI__PPROF_ADDR sets the stage,
127.0.0.1 rules the page.
Hop, hop—configure as you wish!
Profiling served on a custom dish. 🎉

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The PR title accurately reflects the main change: making pprof bind to a configurable loopback address (127.0.0.1:6060) instead of the hardcoded :6060.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/pprof-configurable-addr

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