fix: remove dead CONTRIBUTING.md link, expand auth docs

[KalebCole]

• Contributing: replaced dead CONTRIBUTING.md link with inline dev setup instructions
• Auth Setup: expanded to explain the full SMS flow — auto-retrieve via imsg on macOS, manual fallback on other platforms, creds stored at ~/.config/partiful/auth.json

Summary by CodeRabbit

• Documentation
  • Added "How it works" section under Auth Setup detailing SMS verification flow, including phone format requirements, SMS delivery methods, macOS auto-retrieval options, and credential storage.
  • Enhanced Contributing section with inline development setup instructions.

[coderabbitai]

📝 Walkthrough

Walkthrough

Documentation update to README.md adding a "How it works" section under Auth Setup that describes the SMS verification flow (E.164 phone input, SMS code delivery, optional macOS auto-retrieval via iMessage, manual fallback, and credential persistence) and replacing the Contributing section with inline development setup commands.

Changes

Cohort / File(s)	Summary
Documentation README.md	Added "How it works" subsection under Auth Setup detailing SMS verification flow (E.164 format, SMS delivery, optional iMessage auto-retrieval, manual fallback, credential storage at ~/.config/partiful/auth.json). Replaced Contributing section pointer to external file with inline git clone, npm install, npm link, and npm test commands.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Possibly related PRs

• docs: README overhaul #53: Updates README.md with overlapping Auth setup changes and simplified contribution instructions
• docs: update skill files and add blasts skill #39: Documents the same phone-based SMS authentication flow with E.164 input and code verification
• feat: phone auth with auto SMS code retrieval #38: README documentation covering the SMS-based phone authentication implementation

Poem

🐰 A docs jump so neat, with flows crystal clear,
SMS paths illuminated for all to revere,
From phone to the code, then saved with such care,
Contributing steps now living right there!
No mysteries here—just kindness to share. 📱✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main changes: removing a dead link and expanding authentication documentation.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch pieter/readme-fixes

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

README.md (1)

183-189: Consider documenting the environment variable overrides.

While the documented flow is accurate, the code supports two additional authentication methods that advanced users might find useful:

1. PARTIFUL_CREDENTIALS_FILE — override the default credentials path
2. PARTIFUL_TOKEN — provide an access token directly, bypassing file-based auth

These are currently not mentioned in the README. As per context snippet 1 (src/lib/auth.js:12-37), loadConfig() and resolveCredentialsPath() support these env vars.

📝 Optional addition to document env var overrides

Add after line 188:

 5. Credentials are saved to `~/.config/partiful/auth.json`
+
+**Advanced:** Set `PARTIFUL_CREDENTIALS_FILE` to use a custom credentials path, or `PARTIFUL_TOKEN` to bypass file-based auth entirely.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@README.md` around lines 183 - 189, Update the README near the authentication
flow to document the two env var overrides supported by the code: mention
PARTIFUL_CREDENTIALS_FILE (overrides the default credentials path used by
resolveCredentialsPath()/loadConfig()) and PARTIFUL_TOKEN (directly provides an
access token to bypass file-based auth), and clarify their precedence/behavior
(i.e., PARTIFUL_TOKEN bypasses file loading, PARTIFUL_CREDENTIALS_FILE points
loadConfig() to an alternate path).

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@README.md`:
- Line 186: Update the imsg repository URL in the README entry that currently
links to https://github.com/nicktomlin/imsg; change the link target for the
"imsg" reference to the correct repository URL https://github.com/steipete/imsg
so the README points to the proper CLI tool source.

---

Nitpick comments:
In `@README.md`:
- Around line 183-189: Update the README near the authentication flow to
document the two env var overrides supported by the code: mention
PARTIFUL_CREDENTIALS_FILE (overrides the default credentials path used by
resolveCredentialsPath()/loadConfig()) and PARTIFUL_TOKEN (directly provides an
access token to bypass file-based auth), and clarify their precedence/behavior
(i.e., PARTIFUL_TOKEN bypasses file loading, PARTIFUL_CREDENTIALS_FILE points
loadConfig() to an alternate path).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 6f2def43-3171-48bf-abbb-999a6c61759a

📥 Commits

Reviewing files that changed from the base of the PR and between c1519fc and a38a54f.

📒 Files selected for processing (1)

• README.md

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

🧩 Analysis chain

🌐 Web query:

What is the correct GitHub repository URL for the imsg command-line tool for macOS Messages?

💡 Result:

The correct GitHub repository URL for the imsg command-line tool for macOS Messages is https://github.com/steipete/imsg.

Citations:

• 1: https://github.com/steipete/imsg
• 2: https://imsg.to/
• 3: https://github.com/steipete/imsg/blob/main/AGENTS.md
• 4: https://clawbot.ai/ecosystem/imsg.html

---

Update the imsg repository URL in line 186.

The linked repository is incorrect. The imsg CLI tool is located at https://github.com/steipete/imsg, not https://github.com/nicktomlin/imsg.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@README.md` at line 186, Update the imsg repository URL in the README entry
that currently links to https://github.com/nicktomlin/imsg; change the link
target for the "imsg" reference to the correct repository URL
https://github.com/steipete/imsg so the README points to the proper CLI tool
source.