Revert fork doc edits — make tree identical to upstream

Restore AGENTS.md and .gitignore to upstream. The fork now carries zero patches:
working tree is byte-identical to basecamp/fizzy-cli upstream/master. We still
build the latest (v4.0.0-rc.5) from their source — this only removes our docs.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: waynemsmith

.gitignore

@@ -1,7 +1,6 @@
 # Build artifacts
 bin/
 /fizzy
-/fizzy-fork
 *.exe
 *.exe~
 *.dll

AGENTS.md

@@ -16,24 +16,6 @@ fizzy-cli/
 └── .claude-plugin/      # Claude Code integration
 ```
 
-## Command Architecture
-
-Built on `cobra`. Each command lives in its own file under `internal/commands/`
-(e.g. `card.go`, `board.go`) with a colocated `_test.go`. A command registers
-itself via an `init()` that calls `rootCmd.AddCommand(...)` — there is no central
-registration list. `commands.go` defines `commandCatalogGroups` (core /
-collaboration / admin / utilities), which only controls how `fizzy commands` and
-help group output; adding a command there is cosmetic, not wiring.
-
-`root.go` owns global flags and the output layer. Commands write results through
-the shared `*output.Writer` (`out`) and the raw `outWriter`. Output mode is
-selected by global flags: `--json`, `--agent`, `--styled`, `--markdown`,
-`--quiet`, `--ids-only`, `--count`, `--jq`. Use `isHumanOutput()` to branch
-between styled rendering and structured output, and `printSuccess(data)` /
-breadcrumbs (`output.Breadcrumb`) for machine output. `internal/render/` does the
-styled/markdown/column rendering; `internal/harness/` runs the agent-integration
-health checks behind `fizzy doctor` and `fizzy setup`.
-
 ## SDK Architecture
 
 Commands use the fizzy-sdk (`github.com/basecamp/fizzy-sdk/go/pkg/fizzy`) for API access:
@@ -62,41 +44,16 @@ Key endpoints used by the CLI:
 
 **Important:** Cards use NUMBER for CLI commands, not internal ID. `fizzy card show 42` uses the card number.
 
-## Build & Quality Gates
-
-```bash
-make build            # Build binary to ./bin/fizzy
-make check            # DEFAULT gate: fmt-check + vet + lint + tidy-check + race-test
-make test-unit        # Go unit tests, no API required (./internal/...)
-make lint             # golangci-lint
-```
-
-`make check` is the default target and the local CI gate — run it before
-considering work done. Toolchain: Go 1.26+ managed via `mise` (`.mise.toml`).
-Every build/test target runs `check-toolchain` first, which **fails fast if the
-`PATH` go and `GOROOT` go disagree** — if you hit that, run
-`eval "$(mise hook-env)"` and retry.
-
-### SURFACE.txt — regenerate when the CLI surface changes
-
-`SURFACE.txt` is a golden snapshot of the entire command/flag/arg tree, verified
-by `make surface-check` (a unit test) and in CI. **Any time you add, rename, or
-remove a command, flag, or argument you must regenerate it** or the build fails:
-
-```bash
-make surface-snapshot   # rewrites SURFACE.txt from the current command tree
-```
-
 ## Testing
 
 ```bash
-make test-unit                    # unit tests (no API)
-make test-e2e                     # e2e tests (requires credentials)
-make test-run NAME=TestBoardCRUD  # single e2e test by name
-make test-file FILE=crud_board    # single e2e test file
+make build            # Build binary to ./bin/fizzy
+make test-unit        # Run Go unit tests (no API required)
+make test-e2e         # Run e2e tests (requires credentials)
+make test-run NAME=TestBoardCRUD  # Run a specific test
 ```
 
-E2E tests hit a live API and require credentials (see below). Unit tests do not.
+Requirements: Go 1.26+, API credentials for e2e tests.
 
 ### Unit Test Patterns