Docs: refresh README, promote make build, fix GitHub project scope

[dhilgaertner]

Closes #154

Summary

• Promotes make build to the default Quick Start path (was walking users through ./scripts/build-ghostty.sh + swift build manually)
• Corrects the GitHub auth guidance: the write project scope is required (not read:project) because IssueTracker.markInReview calls the updateProjectV2ItemFieldValue mutation — users following the old instructions hit INSUFFICIENT_SCOPES the first time a ticket moved to In Progress
• Splits long reference material into a new docs/ directory so the README can focus on overview + getting started

New docs

File	Covers
docs/getting-started.md	Clone, make build (+ all Makefile targets), advanced/manual fallback, correct GitHub scopes, CLI permissions table (gh/glab/git/claude), all 9 mise.toml tasks, first-launch wizard aligned with Scaffolder.swift
docs/cli-reference.md	Every subcommand from Packages/CrowCLI/Sources/CrowCLILib/Commands/*.swift — including the previously-missing setup, close-terminal, and the --managed/--command flags on new-terminal
docs/architecture.md	Full 9-package tree, Sources/CrowCLI vs Packages/CrowCLI split, key components with file paths, markInReview data flow
docs/configuration.md	File locations verified against AppSupportDirectory.swift, 4-state TerminalReadiness tied to CrowCore/Models/Enums.swift:41 and SessionListView.swift:325-372
docs/troubleshooting.md	Build + runtime tables; new row for INSUFFICIENT_SCOPES pointing at IssueTracker.swift:691-692,768-769

README changes

• Replaced manual build steps with make build
• Replaced gh auth refresh -s read:project with gh auth refresh -s project,read:org,repo
• Added a callout about read:project being insufficient
• Moved Detailed Setup, Architecture, Configuration, CLI Reference, Development, and Troubleshooting sections into docs/
• Left Features, Contributing, Releases, and License in place

CLAUDE.md changes

• Added close-terminal to the Terminal Commands list
• Added the --managed flag to new-terminal

Keeps the Manager-tab CLI reference in sync with Packages/CrowCLI.

Acceptance criteria from crow#154

• README Quick Start uses make build as the primary build path
• Makefile targets documented (table in docs/getting-started.md)
• GitHub auth section lists correct scopes (repo, read:org, project) and exact gh auth refresh command
• Troubleshooting note clarifying that read:project is insufficient
• CLI tool permissions (gh, glab, git, claude) documented in one place
• mise.toml tasks in docs match actual file (all 9 listed)
• CLI reference matches Packages/CrowCLI source
• Directory structure, file locations, session lifecycle, and terminal readiness verified against current code

Test plan

• From a scratch clone, run just make build per the new Quick Start and confirm it produces .build/debug/CrowApp and .build/debug/crow
• Run gh auth refresh -s project,read:org,repo and confirm gh auth status lists project (not read:project)
• Move a ticket to In Progress via a session and confirm no INSUFFICIENT_SCOPES in [IssueTracker] stderr
• Confirm every relative link from README.md → docs/*.md resolves in the rendered PR view
• Spot-check crow <cmd> --help against docs/cli-reference.md for 2-3 subcommands (e.g. add-worktree, new-terminal, set-ticket)

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