feat(repos): add repo edit subcommand (#928)

## Summary
- Add `tea repo edit` subcommand to update repository properties via the Gitea API
- Support flags: `--name`, `--description`/`--desc`, `--website`, `--private`, `--template`, `--archived`, `--default-branch`
- Boolean-like flags use string type to distinguish "not set" from "false", following the pattern in `releases/edit.go`

## Test plan
- [x] `go build ./...` passes
- [x] `go vet ./...` passes
- [x] `tea repo edit --help` shows all flags correctly
- [x] Manual test: `tea repo edit --private true` on a test repo
- [x] Manual test: `tea repo edit --name new-name --description "new desc"` on a test repo

Reviewed-on: https://gitea.com/gitea/tea/pulls/928
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Co-committed-by: Bo-Yi Wu <appleboy.tw@gmail.com>

docs/CLI.md

@@ -1199,6 +1199,32 @@ Delete an existing repository
 
 **--owner, -O**="": owner of the repo
 
+### edit, e
+
+Edit repository properties
+
+**--archived**="": Set archived [true/false]
+
+**--default-branch**="": Set default branch
+
+**--description, --desc**="": New description of the repository
+
+**--login, -l**="": Use a different Gitea Login. Optional
+
+**--name**="": New name of the repository
+
+**--output, -o**="": Output format. (simple, table, csv, tsv, yaml, json)
+
+**--private**="": Set private [true/false]
+
+**--remote, -R**="": Discover Gitea login from remote. Optional
+
+**--repo, -r**="": Override local repository path or gitea repository slug to interact with. Optional
+
+**--template**="": Set template [true/false]
+
+**--website**="": New website URL of the repository
+
 ## branches, branch, b
 
 Consult branches