Remove built-in chat command in favor of MCP server (#18)

## Why

The built-in `msgvault chat` command implemented RAG
(retrieval-augmented generation) over a local Ollama instance. While it
worked, it was underbaked and took on responsibilities that don't belong
in an archival tool: LLM client management, prompt engineering,
streaming output, and retrieval orchestration.

Meanwhile, the MCP server (`msgvault mcp`) already exposes the full
archive — search, aggregates, message detail, metadata — as a standard
protocol that any AI client can use. This is a better architecture:

- **Claude Desktop** connects directly via MCP
- **OpenWebUI** and other local LLM frontends support MCP tool use, so
Ollama/llama.cpp users get the same integration without msgvault owning
the LLM layer
- **Any future MCP-capable agent** gets archive access for free

Maintaining a bespoke chat implementation alongside MCP means duplicated
effort for a worse result. Removing it lets us focus on making the MCP
server excellent.

## What changed

- Deleted `internal/chat/` package (RAG session, Ollama client, prompts,
tests)
- Deleted `cmd/msgvault/cmd/chat.go` CLI command
- Removed `ChatConfig` from config and `[chat]` section defaults
- Removed `github.com/ollama/ollama` dependency (~914 lines removed)
- Updated README and quickstart docs

## Test plan
- [x] `make build` passes
- [x] `make test` passes
- [x] `make lint` passes
- [x] `msgvault --help` no longer shows `chat` command

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: wesm

README.md

@@ -8,11 +8,11 @@
 
 > **Pre-alpha software.** APIs, storage format, and CLI flags may change without notice. Back up your data.
 
-Archive a lifetime of email and chat. Analytics and search in milliseconds. Query with AI, entirely offline.
+Archive a lifetime of email. Analytics and search in milliseconds, entirely offline.
 
 ## Why msgvault?
 
-Your messages are yours. Decades of correspondence, attachments, and history shouldn't be locked behind a web interface or an API. msgvault downloads a complete local copy and then everything runs offline. Search, analytics, and AI chat all work against local data with no network access required.
+Your messages are yours. Decades of correspondence, attachments, and history shouldn't be locked behind a web interface or an API. msgvault downloads a complete local copy and then everything runs offline. Search, analytics, and the MCP server all work against local data with no network access required.
 
 Currently supports Gmail, with WhatsApp and other messaging platforms planned.
 

cmd/msgvault/cmd/chat.go

@@ -285,16 +285,6 @@ msgvault tui --account user@gmail.com
 | `?`              | Help                                            |
 | `q`              | Quit                                            |
 
-## Chat with your archive (local LLM)
-
-```bash
-# Requires Ollama running locally
-msgvault chat
-msgvault chat --server http://localhost:11434 --model llama3
-```
-
-Interactive RAG-based chat that searches your email archive to answer questions.
-
 ## Typical agent workflow
 
 1. **Check status**: `msgvault stats` — see what's in the archive.

cmd/msgvault/cmd/quickstart.md

@@ -15,7 +15,6 @@ require (
 	github.com/mattn/go-runewidth v0.0.16
 	github.com/mattn/go-sqlite3 v1.14.33
 	github.com/muesli/termenv v0.16.0
-	github.com/ollama/ollama v0.15.2
 	github.com/spf13/cobra v1.10.2
 	golang.org/x/oauth2 v0.34.0
 	golang.org/x/sync v0.19.0
@@ -37,6 +36,7 @@ require (
 	github.com/go-viper/mapstructure/v2 v2.2.1 // indirect
 	github.com/goccy/go-json v0.10.5 // indirect
 	github.com/google/flatbuffers v25.1.24+incompatible // indirect
+	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/invopop/jsonschema v0.13.0 // indirect
@@ -60,7 +60,6 @@ require (
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
 	github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
 	github.com/zeebo/xxh3 v1.0.2 // indirect
-	golang.org/x/crypto v0.43.0 // indirect
 	golang.org/x/exp v0.0.0-20250218142911-aa4b98e5adaa // indirect
 	golang.org/x/mod v0.30.0 // indirect
 	golang.org/x/net v0.46.0 // indirect

go.mod

@@ -103,8 +103,6 @@ github.com/muesli/termenv v0.16.0 h1:S5AlUN9dENB57rsbnkPyfdGuWIlkmzJjbFf0Tf5FWUc
 github.com/muesli/termenv v0.16.0/go.mod h1:ZRfOIKPFDYQoDFF4Olj7/QJbW60Ol/kL1pU3VfY/Cnk=
 github.com/olekukonko/tablewriter v0.0.5 h1:P2Ga83D34wi1o9J6Wh1mRuqd4mF/x/lgBS7N7AbDhec=
 github.com/olekukonko/tablewriter v0.0.5/go.mod h1:hPp6KlRPjbx+hW8ykQs1w3UBbZlj6HuIJcUGPhkA7kY=
-github.com/ollama/ollama v0.15.2 h1:uof4O7frnebDH9wzysMMyWU1aPI8NPJF7guhBOl+5a0=
-github.com/ollama/ollama v0.15.2/go.mod h1:4Yn3jw2hZ4VqyJ1XciYawDRE8bzv4RT3JiVZR1kCfwE=
 github.com/pierrec/lz4/v4 v4.1.22 h1:cKFw6uJDK+/gfw5BcDL0JL5aBsAFdsIT18eRtLj7VIU=
 github.com/pierrec/lz4/v4 v4.1.22/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
@@ -138,8 +136,6 @@ github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN
 github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
 github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
-golang.org/x/crypto v0.43.0 h1:dduJYIi3A3KOfdGOHX8AVZ/jGiyPa3IbBozJ5kNuE04=
-golang.org/x/crypto v0.43.0/go.mod h1:BFbav4mRNlXJL4wNeejLpWxB7wMbc79PdRGhWKncxR0=
 golang.org/x/exp v0.0.0-20250218142911-aa4b98e5adaa h1:t2QcU6V556bFjYgu4L6C+6VrCPyJZ+eyRsABUPs1mz4=
 golang.org/x/exp v0.0.0-20250218142911-aa4b98e5adaa/go.mod h1:BHOTPb3L19zxehTsLoJXVaTktb06DFgmdW6Wb9s8jqk=
 golang.org/x/mod v0.30.0 h1:fDEXFVZ/fmCKProc/yAXXUijritrDzahmwwefnjoPFk=
@@ -156,8 +152,6 @@ golang.org/x/sys v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
 golang.org/x/sys v0.37.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/telemetry v0.0.0-20251008203120-078029d740a8 h1:LvzTn0GQhWuvKH/kVRS3R3bVAsdQWI7hvfLHGgh9+lU=
 golang.org/x/telemetry v0.0.0-20251008203120-078029d740a8/go.mod h1:Pi4ztBfryZoJEkyFTI5/Ocsu2jXyDr6iSdgJiYE/uwE=
-golang.org/x/term v0.36.0 h1:zMPR+aF8gfksFprF/Nc/rd1wRS1EI6nDBGyWAvDzx2Q=
-golang.org/x/term v0.36.0/go.mod h1:Qu394IJq6V6dCBRgwqshf3mPF85AqzYEzofzRdZkWss=
 golang.org/x/text v0.30.0 h1:yznKA/E9zq54KzlzBEAWn1NXSQ8DIp/NYMy88xJjl4k=
 golang.org/x/text v0.30.0/go.mod h1:yDdHFIX9t+tORqspjENWgzaCVXgk0yYnYuSZ8UzzBVM=
 golang.org/x/tools v0.38.0 h1:Hx2Xv8hISq8Lm16jvBZ2VQf+RLmbd7wVUsALibYI/IQ=