feat: add git worktree isolation via port shifting

[bastnic]

Summary

When using git worktrees (e.g. with an AI coding agent working on multiple branches), each worktree needs its own isolated Docker infrastructure — otherwise containers, volumes, networks, and ports conflict.

This PR adds automatic detection of git worktrees and shifts Docker Compose project names and ports accordingly, so each worktree runs its own stack in parallel without modifying /etc/hosts.

How it works

• Detection: parses the .git file (content: gitdir: ...) to detect worktree mode
• Project name: suffixed with -wt-<worktree-name> → Docker Compose isolates containers, volumes, networks automatically
• Ports: derived from a CRC32 hash of the worktree name (range 10000-60000) to avoid collisions
• Domains: kept unchanged — no /etc/hosts modifications per worktree

UX

• castor start now prints the allocated ports at the end
• castor about includes the HTTPS port in URLs when in a worktree
• New castor docker:ports task to display ports at any time
• Outside worktrees: behavior is identical to before (default ports 80/443/8080)

$ castor about

[...]

Available URLs for this project:
--------------------------------

 * https://app.test:30411
 * https://www.app.test:30411

$ castor docker:ports

Ports
=====

 --------------- ------------------------------------
  Worktree        worktree-silver-harbor-5d67
  Project         app-wt-worktree-silver-harbor-5d67
  HTTP            http://app.test:30410
  HTTPS           https://app.test:30411
  Traefik admin   http://localhost:30412
 --------------- ------------------------------------

[Korbeil]

implementation seems nice !
since the worktree usage is clearly agents focused, I think we should bundle a template AGENTS.md with minimum instruction about this worktree support so agents can use it efficiently

[lyrixx]

Nice, but IMHO we could simplify this but not using the context for fews keys

[lyrixx]

Nice ! Except three little comment, I'm 👍🏼

[lyrixx]

So admin port can be null? then the next line will fail :/ could the default value ve 8080? (old defefault one)

[lyrixx]

you already get that var about, L41

[lyrixx]

I wonder if this function should goes to docker.php, WDYT?