refactor: one file per command and per MCP tool; flatten internal/tiger

[nathanjcochran]

Pure file/package reorganization to make the repo easier to navigate. Three changes:

1. Moved everything from internal/tiger/ up into internal/. The extra level of hierarchy wasn't buying us anything.

2. Split the CLI command files so each command gets its own file in internal/cmd/, named to match the command in snake_case (tiger service create → service_create.go). service.go was 2000+ lines and db.go and mcp.go weren't far behind. Group commands keep their own file and hold the helpers shared across their subcommands. Test files follow the same layout, with package-wide test scaffolding in main_test.go.

3. Split the MCP tool files the same way — one file per tool, each laid out as input/output schemas, then a new*Tool() constructor, then the handler. Tool registration moved into server.go, so adding a tool is one new file plus one addTool line.

No behavior changes. The only code that isn't a straight move is the MCP tool registration: the inline &mcp.Tool{...} literals became new*Tool() functions, and registerServiceTools/registerDatabaseTools are now just lists of addTool calls. Everything else is byte-identical to before, verified by diffing every top-level declaration's source text against main.

CLAUDE.md and docs/development.md are updated to describe the new conventions.

[Askir]

Only really looked at the CLI part but that generally looks good to me 👍
I just wonder if we can clear up a bit where the shared helpers actually lie I find it a bit confusing that e.g. checkStdinIsTTY and readPasswordFromTerminal are still in db.go.

I asked claude about other unclear cases and it suggested a rule set like this:

Claude output

1. Used by one command → that command's file.
2. Used by several commands in one group → the group file (db.go, service.go).
3. Used across groups, must stay in package cmd (test-override vars, cobra types) → a named package-level file: completion.go, flag.go, or a new terminal.go.
4. Used across groups, no dependency on cmd → internal/util or internal/common.
5. Used by both CLI and MCP → internal/common (already the documented rule; this just makes it the same rule rather than a separate one).
   Claude Stop

And it says these functions would have to be moved then:

Claude output

• checkStdinIsTTY, readPasswordFromTerminal — in db.go, used by service_update_password.go, read_replica.go, password_recovery.go → rule 3, new terminal.go, joined by readString (currently squatting in root.go).
• generateSecurePassword — in db.go, nothing db-specific, used by the service update-password --auto-generate path → rule 4, internal/util.
• serviceIDCompletion — in service.go, used by both groups → rule 3, completion.go, which exists for exactly this.
• updateNumberBuffer — in oauth.go, borrowed by mcp_install.go → rule 3, alongside the other shared TUI bits.
• password_recovery.go — currently two flows in one file. The rotation trio (promptAndResetPassword → resetServicePassword → updateAndSaveServicePassword) is the genuinely shared kernel and is duplicated in internal/mcp/service_update_password.go → rule 5, internal/common. Everything else (bubbletea menu, testConnectionWithPassword, isAuthenticationError, testSaveAndLaunchPsqlWithPassword) is reachable only from db connect → rule 1, fold into db_connect.go, which also resolves the current password_recovery.go → launchPsql back-reference. File stops existing.

This seems sensible to me, but curious what you think? Not sure if we want to fold it in here if you agree.

Also:

Claude output

• CLAUDE.md:480 and :994 still say .goreleaser.yml; this PR renamed it to .goreleaser.yaml.
• docs/CODE_REVIEW.md (11 refs) and docs/DECISIONS.md:45 still point at internal/tiger/…. Point-in-time artifacts, so arguably delete rather than fix — but they're the only stale paths left in the repo.

[nathanjcochran]

Yes, totally agree that we could (and should) go further with the restructuring. This was just kind of intended to be a big initial push in the right direction, with hopefully more smaller (and easier to review) PRs to follow 🤞.