Docs: Missing documentation for Boost Rules project setting

[novavolcanic]

What's missing or wrong

The Boost Rules feature was added to the project settings UI (PR #78) but is completely undocumented. Admins with boost.enabled access can configure URL pattern rules that automatically apply boost scores during indexing, without needing to add meta tags to individual pages.

Source of truth (code)

Model: biel/apps/projects/models.py:197-217

class BoostRule(models.Model):
    active = models.BooleanField(default=True)
    pattern = models.CharField(max_length=255)
    boost_score = models.FloatField(default=0.0)
    position = models.PositiveIntegerField()
    project = models.ForeignKey(Project, on_delete=models.CASCADE, related_name="boost_rules")

Form fields: biel/apps/projects/forms.py:430-460 — form exposes pattern and boost_score only.

UI access: biel/apps/projects/views/views.py:339-340 — gated behind boost.enabled team permission.

Matching logic: biel/apps/projects/parsers/url_parser.py:1619-1638

• When multiple patterns match a URL, the longest pattern wins (most specific).
• Returns 0.0 if no pattern matches.

Score combining: biel/apps/projects/parsers/url_parser.py:1421

total_boost_score = page_boost_score + filter_boost_score

The rule-based boost score adds to the page-level biel:boost_score meta tag score.

What needs to change in docs

1. Add a "Boost rules" section to docs/administration/projects.md

Add this after the existing "Search filters" section under Project settings:

### Boost rules

Boost rules let you assign search ranking adjustments to groups of pages based on URL patterns, without modifying individual pages.

:::note
Boost rules are available on select plans. Contact support to enable this feature.
:::

Each rule requires:
- **Pattern**: A case-insensitive regular expression matched against full page URLs. For example, `/api/.*` matches all pages under `/api/`.
- **Boost score**: A number that adjusts the page's search ranking. Positive values (for example, `0.5`) increase ranking; negative values (for example, `-0.5`) decrease it.

When multiple rules match a URL, the most specific rule (longest pattern) applies. Rule boost scores combine additively with any page-level `biel:boost_score` meta tag.

For details on boost scoring, see [Boost search results](../customization/search.mdx#boost-search-results).

2. Update docs/customization/search.mdx

In the "Boost search results" section, add a note explaining that the dashboard provides an alternative to page-level meta tags: project administrators can configure boost rules in Settings > Boost rules to apply scores to URL patterns without modifying page HTML.

Style notes

• Use second person, active voice, present tense
• Use sentence case for headings
• Use code font for field names, patterns, and values
• Follow Google developer documentation style guide