fix: revert README to v1.x documentation on main branch

The main branch README currently documents v2 (pre-alpha), which
confuses users who land on the repo expecting stable v1.x docs.

This moves the v2 README content to README.v2.md and replaces
the main README with v1.x-appropriate documentation that uses
FastMCP (the v1.x API) instead of MCPServer (the v2 API).

Key changes:
- README.md now documents v1.x with FastMCP imports/usage
- README.v2.md preserves the full v2/MCPServer documentation
- CI, pre-commit, and snippet tooling updated to target README.v2.md
- Code snippets in README.md use v1.x field names (e.g.,
  structuredContent, inputSchema, uriTemplate)
- pyproject.toml ruff exclude updated for README.v2.md

Both READMEs include TODO(v2) comments marking where to swap
back when v2 is released.

Github-Issue: #1970

Author: maxisbey

.github/workflows/shared.yml

@@ -80,4 +80,4 @@ jobs:
         run: uv sync --frozen --all-extras --python 3.10
 
       - name: Check README snippets are up to date
-        run: uv run --frozen scripts/update_readme_snippets.py --check
+        run: uv run --frozen scripts/update_readme_snippets.py --check --readme README.v2.md

.pre-commit-config.yaml

@@ -42,7 +42,7 @@ repos:
         types: [python]
         language: system
         pass_filenames: false
-        exclude: ^README\.md$
+        exclude: ^README\.v2\.md$
       - id: pyright
         name: pyright
         entry: uv run --frozen pyright
@@ -59,5 +59,5 @@ repos:
         name: Check README snippets are up to date
         entry: uv run --frozen python scripts/update_readme_snippets.py --check
         language: system
-        files: ^(README\.md|examples/.*\.py|scripts/update_readme_snippets\.py)$
+        files: ^(README\.v2\.md|examples/.*\.py|scripts/update_readme_snippets\.py)$
         pass_filenames: false