GRM-45: fix: generate self-contained SVG badges instead of shields.io JSON

shields.io can't fetch JSON from our self-hosted Gitea instance (not
publicly reachable), so badges showed "unknown". Switched to generating
self-contained SVG badge files that are served directly by Gitea's raw
file API — no external service needed.

Changes:
- generate_badges.py: Added render_svg() to produce shields.io-style
  SVG badges with gradient, rounded corners, and Verdana font
- Replaced xml.sax.saxutils.escape with a simple _xml_escape() to
  avoid bandit B406 warning (no defusedxml dependency needed)
- CI workflow: Push .svg files instead of .json to badges branch
- README.md and docs/index.md: Updated badge URLs to use raw SVG
  from the badges branch instead of shields.io endpoint

Also fixed:
- Coverage regex now handles 100% without decimal (was 100.00%)
- doc_coverage.py: Removed redundant % in pct variable that caused
  double-percent (100%%) in output

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

scripts/generate_badges.py

@@ -1,15 +1,9 @@
 #!/usr/bin/env python3
-"""Generate shields.io endpoint badge JSON files from project metrics.
+"""Generate self-contained SVG badge files from project metrics.
 
 Runs pytest-cov, doc-coverage, lint checks, and version extraction,
-then writes JSON files in the shields.io endpoint format:
-
-    {
-        "schemaVersion": 1,
-        "label": "coverage",
-        "message": "100%",
-        "color": "brightgreen"
-    }
+then writes SVG badge files that can be served as static files from
+the Gitea raw file API.
 
 Usage:
     python3 scripts/generate_badges.py --output-dir .badges/
@@ -17,7 +11,6 @@ Usage:
 
 from __future__ import annotations
 
-import json
 import re
 import subprocess  # nosec B404
 from pathlib import Path
@@ -31,15 +24,22 @@ _COVERAGE_RE = re.compile(r"TOTAL.*?(\d+(?:\.\d+)?)%")
 _PASSED_RE = re.compile(r"(\d+) passed")
 _DOC_COVERAGE_RE = re.compile(r"Doc coverage:\s+\d+/\d+\s+\((\d+)%")
 
+# shields.io color names to hex values
+COLOR_HEX: dict[str, str] = {
+    "brightgreen": "#4c1",
+    "green": "#97ca00",
+    "yellowgreen": "#a4a61d",
+    "yellow": "#dfb317",
+    "orange": "#fe7d37",
+    "red": "#e05d44",
+    "blue": "#007ec6",
+    "lightgrey": "#9f9f9f",
+}
 
-def make_badge(label: str, message: str, color: str) -> dict[str, str | int]:
-    """Build a shields.io endpoint badge dict."""
-    return {
-        "schemaVersion": 1,
-        "label": label,
-        "message": message,
-        "color": color,
-    }
+
+def _xml_escape(text: str) -> str:
+    """Escape XML special characters."""
+    return text.replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;").replace('"', "&quot;")
 
 
 def run_command(cmd: list[str]) -> tuple[int, str, str]:
@@ -54,6 +54,50 @@ def run_command(cmd: list[str]) -> tuple[int, str, str]:
     return result.returncode, result.stdout, result.stderr
 
 
+def make_badge(label: str, message: str, color: str) -> dict[str, str | int]:
+    """Build a badge data dict."""
+    return {
+        "schemaVersion": 1,
+        "label": label,
+        "message": message,
+        "color": color,
+    }
+
+
+def render_svg(label: str, message: str, color: str) -> str:
+    """Render a shields.io-style SVG badge."""
+    color_hex = COLOR_HEX.get(color, color if color.startswith("#") else "#9f9f9f")
+
+    # Approximate text width: 7px per character + 10px padding
+    label_text = _xml_escape(label)
+    message_text = _xml_escape(message)
+    label_w = max(len(label) * 7 + 10, 30)
+    message_w = max(len(message) * 7 + 10, 30)
+    total_w = label_w + message_w
+
+    return f'''<svg xmlns="http://www.w3.org/2000/svg" width="{total_w}" height="20" role="img"
+  aria-label="{label_text}: {message_text}">
+  <title>{label_text}: {message_text}</title>
+  <linearGradient id="s" x2="0" y2="100%">
+    <stop offset="0" stop-color="#fff" stop-opacity=".7"/>
+    <stop offset=".1" stop-color="#bbb" stop-opacity=".1"/>
+    <stop offset=".9" stop-color="#000" stop-opacity=".3"/>
+    <stop offset="1" stop-color="#bbb" stop-opacity=".1"/>
+  </linearGradient>
+  <clipPath id="r"><rect width="{total_w}" height="20" rx="3" fill="#fff"/></clipPath>
+  <g clip-path="url(#r)">
+    <rect width="{label_w}" height="20" fill="#555"/>
+    <rect x="{label_w}" width="{message_w}" height="20" fill="{color_hex}"/>
+    <rect width="{total_w}" height="20" fill="url(#s)"/>
+  </g>
+  <g fill="#fff" text-anchor="middle" font-family="Verdana,DejaVu Sans,sans-serif" font-size="11">
+    <text x="{label_w // 2}" y="14">{label_text}</text>
+    <text x="{label_w + message_w // 2}" y="14">{message_text}</text>
+  </g>
+</svg>
+'''
+
+
 def extract_coverage(output: str) -> float | None:
     """Extract total coverage percentage from pytest-cov output."""
     for line in output.splitlines():
@@ -118,7 +162,7 @@ def doc_coverage_color(pct: int) -> str:
 
 
 def generate_badges(output_dir: Path) -> dict[str, dict[str, str | int]]:
-    """Generate all badge JSON files and return them as a dict."""
+    """Generate all badge SVG files and return badge data as a dict."""
     badges: dict[str, dict[str, str | int]] = {}
 
     # 1. Code coverage + test count (single pytest-cov run)
@@ -176,11 +220,12 @@ def generate_badges(output_dir: Path) -> dict[str, dict[str, str | int]]:
     # 5. Python version (static but nice)
     badges["python"] = make_badge("python", "3.12", "blue")
 
-    # Write JSON files
+    # Write SVG files
     output_dir.mkdir(parents=True, exist_ok=True)
     for name, badge in badges.items():
-        path = output_dir / f"{name}.json"
-        path.write_text(json.dumps(badge, indent=2) + "\n")
+        svg = render_svg(str(badge["label"]), str(badge["message"]), str(badge["color"]))
+        path = output_dir / f"{name}.svg"
+        path.write_text(svg)
         click.echo(f"  Generated: {path}")
 
     return badges
@@ -190,10 +235,10 @@ def generate_badges(output_dir: Path) -> dict[str, dict[str, str | int]]:
 @click.option(
     "--output-dir",
     default=str(REPO_ROOT / ".badges"),
-    help="Directory to write badge JSON files.",
+    help="Directory to write badge SVG files.",
 )
 def cli(output_dir: str) -> None:
-    """Generate shields.io endpoint badge JSON files."""
+    """Generate self-contained SVG badge files from project metrics."""
     out = Path(output_dir)
     click.echo(f"Generating badges in {out}...")
     badges = generate_badges(out)