cleanup: remove emojis from CLI output — use plain text indicators

Problem

RTK output is littered with emojis (📌, ❓, 📊, ⚠️, 🔍, ⏭️, etc.) — 108 occurrences across 24 source files. This causes several issues:

1. Terminal compatibility: Some terminals, SSH sessions, and CI logs render emojis as ? or garbled characters
2. Professionalism: CLI tools targeting developers should use plain text indicators, not emojis
3. Pipe/grep friendliness: Emojis are multi-byte UTF-8, making grep and text processing harder
4. Inconsistency: Some modules use emojis, others don't — no unified style

Scope

108 emoji occurrences across 24 files:
- git.rs (14), init.rs (27), gh_cmd.rs (12), summary.rs (9)
- ls.rs, display_helpers.rs, runner.rs, log_cmd.rs, gt_cmd.rs...

Proposed replacements

Emoji	Replace with
📌	(branch indicator, or just the branch name)
❓	? or Untracked:
📊	(remove, or Summary:)
⚠️	warning:
🔍	(remove)
⏭️	skipped:
✓	ok or pass
❌	FAIL
✅	ok

Exception

ok ✓ is borderline acceptable as a compact success indicator (single character, widely supported). Can be kept or replaced with ok.

Files to update

src/git.rs, src/init.rs, src/gh_cmd.rs, src/summary.rs, src/ls.rs, src/display_helpers.rs, src/runner.rs, src/log_cmd.rs, src/gt_cmd.rs, src/diff_cmd.rs, src/container.rs, src/env_cmd.rs, src/grep_cmd.rs, src/gain.rs, src/next_cmd.rs, src/pip_cmd.rs, src/pytest_cmd.rs, src/ruff_cmd.rs, src/prisma_cmd.rs, src/format_cmd.rs, src/lint_cmd.rs, src/go_cmd.rs, src/ccusage.rs, src/cc_economics.rs

Snapshot tests will need updating after this change.