feat(cli): --color for --format text output

[digizeph]

--format text printed everything in one color, so session keys, section headers, prefixes and next-hop values were hard to tell apart at a glance. This adds an opt-in ANSI accent layer. Closes #342.

Behavior

• --color <auto|always|never>, default auto: auto colors only when stdout is a terminal, so pipes, redirects and log files stay byte-identical to today. NO_COLOR disables coloring and CLICOLOR_FORCE forces it.
• Only --format text is colored; json/json-pretty/psv/default are untouched.
• Accents use the basic ANSI attributes rather than fixed RGB values, so they follow the reader's terminal theme and stay legible on light and dark backgrounds: bold blue labels, bold magenta section headers, green prefixes, yellow next-hop values.
• Library: render::text::Style::ansi() with format_record_with_style and format_record_with_hex_and_style. format_record keeps returning plain text, and Style::plain() output is byte-identical to it.

Notes

Styling is a post-pass over the block format_record renders rather than a change to the renderer, so the unstyled text cannot drift: a line the accent table does not recognize is copied through untouched, and only a missing accent (cosmetic) is possible. Tests pin strip_sgr(styled) == plain for a record whose MP_REACH_NLRI carries a comma-joined global + link-local next hop, that validation warnings are not mistaken for identifiers, and the auto/NO_COLOR/CLICOLOR_FORCE policy.

[Copilot]

🟡 Changes recommended

Table-dump prefix values do not receive the advertised prefix accent.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds opt-in ANSI styling to human-readable MRT record output.

Changes:

• Adds --color auto|always|never with environment overrides.
• Introduces styled text-rendering APIs and tests.
• Documents the feature in the changelog.

File summaries

File	Description
src/render/text.rs	Implements ANSI post-processing and tests.
src/bin/main.rs	Adds CLI color policy and styled output routing.
CHANGELOG.md	Documents color support.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Balanced

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[codecov]

Codecov Report

❌ Patch coverage is 95.73460% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.56%. Comparing base (faeab92) to head (238cf1f).

Files with missing lines	Patch %	Lines
src/render/text.rs	95.73%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #343      +/-   ##
==========================================
+ Coverage   91.50%   91.56%   +0.06%     
==========================================
  Files         103      103              
  Lines       26487    26698     +211     
==========================================
+ Hits        24236    24446     +210     
- Misses       2251     2252       +1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[Copilot]

🟡 Changes recommended

Several renderer-defined path-attribute labels incorrectly remain unstyled.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

Suppressed comments (1)

src/render/text.rs:200

• ATOMIC_AGGREGATE is rendered as a bare property name without a colon, so it always falls through here and remains unaccented while other path-attribute names are colored. Handle this renderer-owned bare label explicitly.

        } else {
            None

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

🔵 Needs a closer look

Some ANSI spans color metadata beyond the documented role-based palette.

Review details

Suppressed comments (2)

Previously missed (1) — in code that hasn't changed since the last review.

src/render/text.rs:163

• For ANNOUNCED (labeled), trimmed also contains labels=[…] and an optional path-id, so this paints routing metadata green along with the prefix. The documented palette assigns green specifically to prefixes; isolate the first whitespace-delimited prefix and leave the suffix unstyled.

This issue also appears on line 194 of the same file.

src/render/text.rs:197

• The MP_REACH_NLRI branch colors the entire value—including the AFI/SAFI and next-hop text—and even colors the family when no next hop exists. This contradicts the documented role palette where only next-hop values are yellow; split the rendered value at next-hop and accent only the address portion.

            } else if NEXT_HOP_LABELS.contains(&label) {
                Some(format!(
                    "{ANSI_LABEL}{label}:{ANSI_RESET} {ANSI_NEXT_HOP}{value}{ANSI_RESET}"
                ))

• Files reviewed: 3/3 changed files
• Comments generated: 0 new
• Review effort level: Balanced

[Copilot]

🟡 Changes recommended

A new next-hop styling assertion contradicts the implementation and will fail.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Balanced

[Copilot]

🟢 Approval recommended

The implementation preserves existing output by default and adequately tests styling and color-selection behavior.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 0 new
• Review effort level: Balanced