refactor: convert f-string logging to lazy %-style format (G004)

Sweep all 1676 G004 violations across 112 files, converting
`logger.<level>(f"…{x}…")` to `logger.<level>("…%s…", x)`.

Why: ruff rule G004 was added to pyproject.toml to enforce lazy
%-style logging — defers formatting until the log level is enabled
and lets structured log tooling match the unformatted template.

Conversion preserves rendered output byte-for-byte:
- `{x}` → `%s` + `x`
- `{x!r}` / `{x!s}` / `{x!a}` → `%r` / `%s` / `%a`
- Format specs (`{x:.2f}`, `{x:>10}`) → `%s` + `format(x, 'spec')`
  (printf-style specs aren't 1:1 with Python format specs, so we
  delegate to `format()` to keep identical output)
- Literal `%` → `%%`
- Concatenated f-strings (`f"a {x} " "b"`) flattened
- Trailing kwargs (`exc_info=True`) preserved

Verified:
- `uv run ruff check --select G004` → 0 violations
- `uv run ty check -- nextcloud_mcp_server` → passes
- `uv run pytest tests/unit/` → 1010 passed

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

nextcloud_mcp_server/client/base.py

@@ -43,7 +43,8 @@ def retry_on_429(func):
                 # error we wait a couple of seconds and do a retry
                 if e.response.status_code == codes.TOO_MANY_REQUESTS:
                     logger.warning(
-                        f"429 Client Error: Too Many Requests, Number of attempts: {retries}"
+                        "429 Client Error: Too Many Requests, Number of attempts: %s",
+                        retries,
                     )
                     # Record retry metric (extract app name from args if available)
                     if len(args) > 0 and hasattr(args[0], "app_name"):
@@ -53,17 +54,26 @@ def retry_on_429(func):
                     # 404 errors are often expected (e.g., checking if attachments exist)
                     # Log as debug instead of warning
                     logger.debug(
-                        f"HTTPStatusError {e.response.status_code}: {e}, Number of attempts: {retries}"
+                        "HTTPStatusError %s: %s, Number of attempts: %s",
+                        e.response.status_code,
+                        e,
+                        retries,
                     )
                     raise
                 else:
                     logger.warning(
-                        f"HTTPStatusError {e.response.status_code}: {e}, Number of attempts: {retries}"
+                        "HTTPStatusError %s: %s, Number of attempts: %s",
+                        e.response.status_code,
+                        e,
+                        retries,
                     )
                     raise
             except RequestError as e:
                 logger.warning(
-                    f"RequestError {e.request.url}: {e}, Number of attempts: {retries}"
+                    "RequestError %s: %s, Number of attempts: %s",
+                    e.request.url,
+                    e,
+                    retries,
                 )
                 raise
 
@@ -127,7 +137,7 @@ class BaseNextcloudClient(ABC):
             Response object
         """
         url = self._resolve_url(url)
-        logger.debug(f"Making {method} request to {url}")
+        logger.debug("Making %s request to %s", method, url)
 
         # Start timer for metrics
         start_time = time.time()